1. Field of the Invention:
This invention relates to a machine and method for sheathing bales of farm crop, e.g. hay, and particularly to features that are directed to adapting the bale sheathing concept to commercial application.
2. Background of the Invention:
The storage of farm crops has progressed through a series of changes over recent years. Farm crops were for many years either stored in buildings, e.g. silage stored in a silo, grain stored in grain bins and hay stored in hay mows; or they were stored outside, e.g., hay was gathered into stacks or bound up in bales to be stacked and stored in the field.
More recently it has been recognized that huge plastic bags can be advantageously used to replace the storage buildings with substantial benefits. Initially the bags were used to replace silos by storing silage in plastic bags as large as 8 to 10 feet in diameter and 200 feet in length. Machines were specially built to perform the task of filling the bags and they were the subject of numerous improvements that were patented. U.S. Pat. No. 3,687,061 (Eggenmuller), U.S. Pat. No. 4,046,068 (Eggenmuller), U.S. Pat. No. Re 31,810 (Lee) and U.S. Pat. No. 4,337,805 (Johnson, et al) are representative of the improvements that were developed for the specific task of filling large plastic bags with silage.
Machines have more recently been developed for filling large plastic bags with grain. Grain is very different than silage. While both are presented to the bag as loose material, silage is compressible, a property that offers advantages as well as disadvantages compared to grain which flows more like a liquid and does not lend itself to stacking or packing. Machines have been developed specifically for grain bagging in consideration of the difference as represented by the commonly assigned application for U.S. patent filed Mar. 19, 1991, Ser. No. 671,386. The present invention deals with the special problems of bagging crops that have been bound into compacted bales, e.g., hay, straw, grass and the like.
Typically such bales have been stacked on the ground and a certain percentage of the baled material was sacrificed to the elements. Alternatively, the bales were stored in buildings with the attendant added cost of handling and building storage. An object of the present invention is to obviate these problems by storing the bales in plastic bags.
One of the considerations for all three forms of bagging is to avoid inadequate filling which produces a loose fitting bag. A filled bag is considered desirable to reduce the availability of air in the bags and to reduce the likelihood of tearing as a result of the loose fitting bag. In the case of silage and grain, the materials are stuffed into the bags. The stuffing process involves controlled braking whereby the bag length is drawn off the machine by pressure feeding of the loose material into the bag.
In the case of the bales, the material within the bales is already compacted into a large, heavy, rigid shape. Providing a bag of the right size to fit the bales and placing the bales into a tightly dimensioned plastic bag is not easily accomplished. The size of the bales produced by the baling machines have some variance in diameter adding to the problem. It is not feasible to slide the bale into a tight fitting bag. The bale, which is basically rigid, will readily tear the bag when the bale is either forced into the bag or attempts are made to slide the bag over the bale. Accordingly, in order to either slide the bale into the bag or slide the bag under the bale a much larger diameter bag than that of the bale is required resulting in the undesired loose fit.
The problem of the loosely fitting bag for compacted bales was addressed by David J. Cundall. Cundall initially developed a bale bagging machine which is disclosed in U.S. Pat. No. 4,606,176. This patent did not address the problem of the loose fitting bag, but Cundall was made aware of the problem in the subsequent development of the machine. Cundall's solution was to use a bag having elastic properties. The bag opening was fitted to a plurality of circumferentially arranged posts. The posts were mounted on arms that pivoted the posts from a closed opening to an oversized, i.e., stretched opening that exceeded the size of the bales. The bales were then placed into the bag and as the bag was pulled off the posts, it collapsed around the bales to conform closely to the shape of the bale, squeezing out the unwanted air in the process. In that the bag was thereby conformed tightly to the bale configuration, the chance of tearing the bag was substantially reduced. This latter improvement is disclosed in an International Application Number PCT/GB90/01820 filed Nov. 23, 1990 and published Jun. 13, 1991.
Whereas Cundall is believed to have invented the basic concept for elastically bagging hay bales and the like, a number of problems remained. The mechanism for moving the posts in and out was complex, it required power that often exceeded the available power of conventional farm tractors, and it was not acceptably adjustable for different sized bales. Furthermore, the concept of loading the bales into the bag required the machine to be driven through the bales. That is, a tractor carried the machine which was extended to one side of the tractor and as each bale was engaged, the machine raised the bale and guided it through the ring of posts. A high resistive load was applied against the machine which generated a high moment arm of force against the tractor. The bales contemplated herein are 4-5 feet in diameter and weigh many hundreds of pounds. The resistive force of such heavy bales applies a side shifting force that makes steering of most farm tractors difficult or impossible.